Question

what is the GC-MS in the Preparation of cyclohexene from cyclohexanol experiment ? (type it)

Answer 1

Answer.

GC-MS stands for Gas chromatography-mass spectrometer. It is a technique which combines the method used to separate gas-liquid by chromatographic properties and mass spectrometry to detect and identify different compounds present within a test sample. This method identifies the analyte on the basis of its mass.

Cyclohexene is produced by dehydration of cyclohexanol. After conversion of cyclohexanol to cyclohexene, the reaction mixture contains cyclohexene, water and other impurities. Water is carefully removed by adding anhydrous magnesium sulphate or substances like this which absorb water. Then the resultant product contains cyclohexene and impurities.

They are separated and identified through GC-MS. The mixture is heated upto bowling point of cyclohexene ( because it is considerably low than boiling point of the impurities present) which is approximately around 85.5^oC after which it distillated as a gas from rest of the liquid impurities. The distillate is then observed using a mass-spectrometer which shows the molecular weight of the yielded product which should come close to the theoretical molecular weight of cyclohexene (=82), which proves that the product obtained is purely cyclohexene.

The GC-MS is a great tool since it gives accurate results.